Thrust roller bearing cage and thrust roller bearing

Abstract

A thrust roller bearing cage having pockets for accommodating rollers includes an inner annular portion and cage bars that extend in a radial manner from a radially outer edge of the inner annular portion so as to separate the pockets from each other in a circumferential direction. The inner annular portion has a first axial end surface and a second axial end surface. The first axial end surface has an oil passage groove for guiding lubricating oil to the pockets. The second axial end surface is recessed relative to the first axial end surface in an axial direction of the inner annular portion so as to form a recessed portion that communicates with the oil passage groove. The entire region of the first axial end surface that is located radially directly inside the cage bars is located radially outside the second axial end surface.

What is claimed is: 
     
       1. A thrust roller bearing cage having a plurality of pockets for accommodating rollers, the cage comprising;
 an inner annular portion having an axial direction, a radial direction, and a circumferential direction; and 
 a plurality of cage bars extending in a radial manner from a radially outer edge of the inner annular portion so as to separate the plurality of pockets from each other in the circumferential direction, wherein 
 the inner annular portion has a first axial end surface and a second axial end surface, 
 the first axial end surface has an oil passage groove for guiding lubricating oil to the plurality of pockets, 
 the second axial end surface is recessed, relative to the first axial end surface in the axial direction of the inner annular portion so as to form a recessed portion that communicates with the oil passage groove, 
 the first axial end surface has a region that is located radially directly inside the plurality of cage bars, and 
 the entire region is located radially outside the second axial end surface. 
 
     
     
       2. The thrust roller bearing cage according to  claim 1 , wherein
 the second axial end surface has an annular shape and is located around a radially inner edge of the inner annular portion. 
 
     
     
       3. A thrust roller bearing comprising:
 the thrust roller bearing cage according to  claim 2 ; 
 a plurality of rollers retained by the thrust roller bearing cage; and 
 a pair of bearing washers having raceways where the plurality of rollers roll, the pair of bearing washers sandwiching the thrust roller bearing cage in the axial direction. 
 
     
     
       4. The thrust roller bearing cage according to  claim 1 , wherein
 the second axial end surface has a connection portion that is connected to the oil passage groove, and 
 a width of the connection portion in the circumferential direction decreases outward in the radial direction of the inner annular portion. 
 
     
     
       5. A thrust roller bearing comprising:
 the thrust roller bearing cage according to  claim 4 ; 
 a plurality of rollers retained by the thrust roller bearing cage; and 
 a pair of bearing washers having raceways where the plurality of rollers roll, the pair of bearing washers sandwiching the thrust roller bearing cage in the axial direction. 
 
     
     
       6. The thrust roller bearing cage according to  claim 1 , wherein
 the oil passage groove has an opening in a radially inner wall surface of each of the plurality of pockets. 
 
     
     
       7. A thrust roller bearing comprising:
 the thrust roller bearing cage according to  claim 6 ; 
 a plurality of rollers retained by the thrust roller bearing cage; and 
 a pair of bearing washers having raceways where the plurality of rollers roll, the pair of bearing washers sandwiching the thrust roller bearing cage in the axial direction. 
 
     
     
       8. The thrust roller bearing cage according to  claim 1 , wherein
 the oil passage groove has a portion that is located in the plurality of cage bars in the first axial end surface and that has an opening in a side wall surface of each of the plurality of pockets, and 
 the side wall surface faces in the circumferential direction. 
 
     
     
       9. A thrust roller bearing comprising:
 the thrust roller bearing cage according to  claim 8 ; 
 a plurality of rollers retained by the thrust roller bearing cage; and 
 a pair of bearing washers having raceways where the plurality of rollers roll, the pair of bearing washers sandwiching the thrust roller bearing cage in the axial direction. 
 
     
     
       10. A thrust roller bearing comprising:
 the thrust roller bearing cage according to  claim 1 ; 
 a plurality of rollers retained by the thrust roller bearing cage; and 
 a pair of bearing washers having raceways where the plurality of rollers roll, the pair of bearing washers sandwiching the thrust roller bearing cage in the axial direction.